Garmin APOLLO GX SERIES, Service Manual

Page: 76 / 166

Garmin AT Rev --
7-38 GX Service Manual © 2004 Garmin AT
Step General Instruction Specific Instructions Expected Results
5 On the HP8920 DIST field,
select the % field; then SHIFT
(BLUE KEY) REF SET. Push
CURSOR CONTROL knob. Set 1 kHz tone to reference
reading 0.00 dB.
6 On the test box, press the PTT
switch to RX.
7 NOTE: Option 019
required HP8920A. If Option 019 (the notch filter
option) is not installed, an
external variable notch filter will
be required to perform the
following test.
8 On the HP8920, use the SHIFT
(blue key) CONFIG keys under
SCREEN CONTROL and set the
Notch Coupl. to AFGen1. Push
the PREV key under SCREEN
CONTROL to return to TX TEST. Lock notch filter to AF Gen1
Freq.
9 Change notch filter
freq. to 350 Hz. On the HP8920, set the AF
Gen1 Freq. to 350 Hz.
10 On the test box, press the PTT
switch to TX.
11 Record distortion. Will be <10% distortion at 85%
modulation.
12 On the test box, press the PTT
switch to RX.
13 Repeat steps 9 to 13 for every
300 Hz until 2500 Hz is reached. Audio frequency distortion will
be <10% at AM Depth of 85%
at 350 Hz to 2500 Hz.
Frequency Tolerance
Step General Instruction Specific Instructions Expected Results
1 Set all test
equipment as
specified in Test
Equipment Setup on
page 7-17.
Set TX Freq. Error on HP8920 to
PPM.
2 Key transmitter. On the test box, press the PTT
switch to TX.
3 Record Freq. Error. Record TX Freq. Error from
HP8920.
± 15 PPM from -20
°
C to +70
°
C.
4 Un-key transmitter. On the test box, press the PTT
switch to RX.
5 Repeat this test at frequency
118.0 MHz and 136.975 MHz.
± 15 PPM from -20
°
C to +70
°
C.